Over many years of research in the field of liquid crystals, the present inventor, Professor Edward F. Carr of the University of Maine, has documented the occurrence of anamolous ordering and alignment effects of liquid crystal fluids in the presence of electric and magnetic fields, constructed models of the ordering and alignment effects, and provided explanations for these effects which have their origin in the conductivity and dielectric anisotropy characteristic of mesomorphic phase materials. In the chapter entitled "Domains Due to Electric and Magnetic Fields in Bulk Samples of Liquid Crystals", Liquid Crystal and Ordered Fluids, Vol. 3, edited by Johnson & Porter, Plenum Publishing Corporation (1978), the present inventor describes the occurrence of ordered domains separated by walls constituting defects in a nematic liquid crystal fluid when fields are applied perpendicular to the nematic director. The author proposed that an electric field applied across the fluid interacts with space charge associated with the conductivity anisotropy of the fluid to produce shear flow. This shear flow forms the walls which are a special type of defect in the molecular alignment separating the domains. Because of the shear flow the director associated with the liquid crystal fluid is turned toward the electric field.
Liquid crystals or liquid crystal fluids are mesomorphic phase materials exhibiting characteristics intermediate between crystalline solids and true amorphous liquids. Liquid crystals are usually composed of strongly elongated molecules with a tendency toward ordering and alignment of the molecules characteristic of solid crystals but retaining relative motion and flow between the molecules. Liquid crystals generally fall into three categories according to the characteristic modes of self ordering of the molecules, nematic, smectic, and cholesteric. Where the liquid crystal material is characterized by self alignment orientation of the elongate axis molecules, the alignment orientation along the elongate axes is referred to as the director.
Liquid crystal fluids and materials retain their mesomorphic phase characteristics up to a clearing point temperature or transition temperature at which the fluid undergoes a transition to a normal liquid phase. Below the clearing point temperature or transition point temperature, however, the liquid crystal fluid typically exhibits dielectric anisotropy, electrical conductivity anisotrophy, and is expected to exhibit thermal conductivity anisotropy in different directions relative to the orientation of the director. The extent of anisotropy in liquid crystal fluids varies over a range from weak to strong according to the particular materials. Mixtures of different liquid crystal materials are typically combined to provide a liquid crystal fluid of desired characteristics and such mixtures are available from commercial sources such as Merck Liquid Crystal Mixtures, EM Chemicals, P.O. Box 8500, Philadelphia, PA 19178.
In the article "Surface Deformation and Walls in the Conduction Regime of Nematic Liquid Crystals", Molecular Crystals and Liquid Crystals, Vol. 64 letters), pp. 299-304, Gordon and Breach Science Publishers, Inc. (1981), the present inventor with Kozlowski further documented that the anamolous ordered domains occurring in liquid crystal fluids in the presence of an electric field constitute flow cells driven by the shear flow in turn resulting from interaction between the electric field and the characteristic conductivity and dielectric anisotropy of the fluid. The volume of fluid in each domain or flow cell makes many rotations while the walls appear stationary though the material of which they are composed is constantly changing and moving with the maximum fluid velocity. Observations of the movement of dust particles with a microscope at the air-to-liquid crystal interface clearly show that there are flow cells as indicated. These observations were made using a special sample cell open at the top and with vertical electrodes.